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Talk:Approximations of π

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real difficulty in finding where I had gone wrong. But at this point I not only found my figures differing completely from those of Shanks, but all my efforts to find my mistake failed." He spent another four months checking his work by means of a different series summation before venturing the opinion that Shanks might have erred.
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I think it would be better to just say that these cultures had formulas for circumference and area which are equivalent to the formulas C=(25/8)D and A=(256/81)r^2 so it is like they had values for pi, but it wasn't like they were using the formulas C=pi*D and A=pi*r^2 and they were trying to use the
1862:
A fuller account of Ferguson's confrontation with Shanks. Working with a desk calculator, it took him a year to get up to 530 decimal places. "Up to this point, whenever I had disagreed with Shanks' figures (and this has occurred from time to time, owing to copying errors, etc.), I had never had any
1828:
note was from 1946 and didn't say what in year the calculation was supposedly done (it just says "recently"). 1944 is hard to believe because it was the height of WW2 and it's implausible that anyone with the necessary skills would be spending their time calculating pi, as well as tying up a scarce
633:
Currently the article mentions 125648/39995 as a fraction that produces 8 correct digits. This is not wrong, but it's not useful. There are at least 45 better fractions that do the same, and use smaller denominators. And half of then are more accurate. So I am replacing 125648/39995 with 99733/31746
630:
Another use is integer math. For example, if you use integer math with 32 bit numbers to calculate the circumference of an object, and the maximum diameter of that object is 130000 units, then the max denominator would be, 2^32/130000 = 33038. Then the best approximate fraction you can use, would be
917:
But for Egypt, this is much more of a stretch. They have a formula for the area of a circle which is A=(D-D/9)^2. It is a great formula, but to say "treats pi as 256/81" is really not accurate. While it is true that this formula could be written as A=(2r-2r/9)^2=(16r/9)^2=256/81*r^2 it is not
913:
For the babylonians, they have a tablet that basically says that the circumference of a circle is 25/24 multiplied by the perimeter of the inscribed regular hexagon. So if the circle has diameter=1, the side of the hexagon is 0.5 and the perimeter of the hexagon is 3 so the circumference of the
1403: 1226:{\displaystyle \pi \approx \pi _{1}(n)={\frac {3}{(1-R){\sqrt {n}}}},\quad R={\frac {1-{\frac {3}{\pi {\sqrt {n}}}}-24\sum _{r=1}^{\infty }{\frac {r}{\exp(2\pi r{\sqrt {n}})-1}}}{1-24\sum _{r=1}^{\infty }{\frac {2r-1}{\exp(\pi (2r-1){\sqrt {n}})+1}}}}} 847: 2027: 1760:{\displaystyle \pi _{4}(n)={\frac {6}{(1-S){\sqrt {n}}}},\quad S={\frac {1-{\frac {6}{\pi {\sqrt {n}}}}-24\sum _{r=1}^{\infty }{\frac {r}{\exp(\pi r{\sqrt {n}})-1}}}{1+24\sum _{r=1}^{\infty }{\frac {2r-1}{\exp(\pi (2r-1){\sqrt {n}})-1}}}}} 1482: 1829:
desk calculator for however long it was. By 1946 there would have been plenty of people with time on their hands, plus surplus calculators. I have not looked at the Penguin book about curious numbers cited in the
1876:
and indicates the calculation really was done in 1944-1945, wow. I'll change my earlier edit in a minute, and expand the article a little bit when I get a chance. I haven't yet looked Hayes' other references.
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Aside from some mathematical trivia, generally a good use of approximation of pi would be for the memorization of a smaller number of digits than the approximation can give. For this, only 355/113 is useful.
1905:
In 1853 there appeared, in a paper by W. Rutherford, the value of the constant π to 530 decimals, calculated by W. Shanks. This was eventually extended by Shanks to 607, and in 1873 to 707 decimals.
925:
Might there be a simple way to edit this so that it is more accurate and does not claim that these cultures were aware there there was this constant pi, but not to make it too complicated to explain?
2075:
It is tempting to look at the version of the BBP formula given and think that the 16 factor at the end implies that the rest returns the value of one digit but this is obviously not the case, as the
2089:
Could someone better at this stuff than me please add a formula that actually returns arbitrary digits of π? Or, if this is actually not possible, the article text needs to be updated to say so.
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circle would be 25/24*3=25/8=3 1/8. So this is a formula for circumference of a circle, basically 25/8 * diameter, so it is not totally wrong to say 'by implication treats pi as 25/8".
1795:
This section has become a magnet for the insertion of ad hoc approximations of a few decimal places that anyone can dream up. I recommend removing the section altogether per
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the formula can compute any particular digit of π—returning the hexadecimal value of the digit—without having to compute the intervening digits (digit extraction).
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It's quite frustrating that the section titled "digit extraction methods" doesn't actually state a way of extracting a digit of π, in any base. It states that
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It is of interest to note that the discrepancy occurs at about the point to which Shanks's first published value extends, that is, in the 530th decimal.
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The value so obtained agrees with Shanks's value only to the 527th decimal place; from that last point it seems that Shanks's value is incorrect.
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But then, bizarrely, doesn't give a formula for extracting any particular digit of π, instead giving a series sum to return the value of π.
1868:
This and a few others from Hayes' list look like better references about the Ferguson calculation. The mathematical Gazette article is at
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Likewise, Plouffe's formula for digits of π in base 10 is only given as a sum with no obvious way to factor it into individual digits.
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For more than seventy years this has been accepted as the value of π, apparently without any doubts having been expressed in print.
626:
The entries with the '<' signs are particularly interesting because of the ratio of added precision over increase of denominator.
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The problem is that neither of those cultures had yet a concept of pi as either circumference/diameter or as area/(radius^2).
2054: 1842: 1398:{\displaystyle \pi _{1}(58)={\frac {1037785473+70101072{\sqrt {2}}+192518946{\sqrt {29}}+311451846{\sqrt {58}}}{1446914567}}} 2079:
factor only appears in denominators and so all the terms in the first part of the sum will become infinitesimally small as
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http://math.stackexchange.com/questions/1097633/how-to-show-frac-pi4-frac2-cdot4-cdot4-cdot6-cdot6-cdot8-dotsm3-cdot
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be mentioned on this page or is it too obscure? It does seem that some books use it at leas as an example; see
284:
Here is a list of fractions giving approximations of pi with increasing denominators and increasing precision:
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Ferguson, D. F. 1946. Evaluation of π. Are Shanks' figures correct? The Mathematical Gazette 30(289):89–90.
926: 674: 50: 94: 1781: 2094: 842:{\displaystyle {\sqrt {2}}+{\sqrt {3}}+{\frac {{\sqrt {2}}-{\sqrt {3}}-18}{3921}}=3.141592644\ 0^{+}} 245: 1855: 1785: 32: 1804: 116:
on Knowledge. If you would like to participate, please visit the project page, where you can join
1796: 1777: 205: 100: 903:≈ 3.16 (accurate to 0.6 percent) by calculating the area of a circle via approximation with the 738: 714: 84: 63: 2022:{\displaystyle \pi =12\tan ^{-1}{1 \over 4}+4\tan ^{-1}{1 \over 20}+4\tan ^{-1}{1 \over 1985}} 1890: 1869: 854: 639: 201: 176: 1911:
Recently I decided to test numerically a series found by a colleague, R. W. Morris, namely
872:
in 1936 (dated to between the 19th and 17th centuries BCE) gives a better approximation of
2090: 1408:
is complicated. The Borwein's brothers mention the following approximation in their book.
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which yields Pi accurately to 10 decimal places..if you need that much accuracy, but
643: 273: 257: 649:...if I may..I find it difficult to memorize any of those fractions after 355/311. 850: 635: 113: 203: 652:
however, I'd like to go the other way and suggest the following approximation:
90: 849:
is accurate to 8 digits. But I don't think it's worth adding to the article.
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I changed the claimed date of this calculation from 1944 to 1946, to match
1889:(Ferguson, D. F. (16 March 1946). "Value of π". Nature. 157 (3985): 342. 1477:{\displaystyle \pi _{4}(58)={\frac {66{\sqrt {2}}}{33{\sqrt {29}}-148}}} 624:
5419351 / 1725033 = 3.14159265358981 (0.0000000000007068% err) <<
904: 693:"Approximations" of pi are mostly best geometry, rational exhaustion. 1894: 1873: 1302:{\displaystyle \pi _{1}(25)={\frac {9}{5}}+{\sqrt {\frac {9}{5}}}} 696:
Here that's "at least as mucn precision, ..., as 7 digits of pi".
314:
355 / 113 = 3.141592920 (0.0000084914% err) <<<<<
1885:
Regarding the above, here is the contents of Ferguson's note in
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1146408 / 364913 = 3.1415926535914 (0.00000000005127% err) <
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The values from the 521st to 540th decimals are given below:
622:
4272943 / 1360120 = 3.1415926535894 (0.000000000012863% err)
620:
3126535 / 995207 = 3.1415926535886 (0.00000000003637% err)
614:
312689 / 99532 = 3.14159265362 (0.0000000009276% err) <
891:, c. 1600 BCE, although stated to be a copy of an older, 610:
104348 / 33215 = 3.14159265392 (0.00000001055% err) <
616:
833719 / 265381 = 3.141592653581 (0.0000000002774% err)
1818: 868:"one Old Babylonian mathematical tablet excavated near 1919: 1496: 1417: 1321: 1251: 953: 768: 741: 717: 612:
208341 / 66317 = 3.14159265347 (0.000000003894% err)
1776:
is even. I added this approximation to the article.
608:
103993 / 33102 = 3.14159265301 (0.00000001839% err)
606:
103638 / 32989 = 3.14159265210 (0.00000004754% err)
604:
103283 / 32876 = 3.14159265117 (0.00000007689% err)
602:
102928 / 32763 = 3.14159265025 (0.00000010644% err)
112:, a collaborative effort to improve the coverage of 2021: 1759: 1476: 1397: 1301: 1225: 841: 751: 727: 600:102573 / 32650 = 3.1415926493 (0.0000001362% err) 598:102218 / 32537 = 3.1415926483 (0.0000001661% err) 596:101863 / 32424 = 3.1415926474 (0.0000001963% err) 594:101508 / 32311 = 3.1415926464 (0.0000002267% err) 592:101153 / 32198 = 3.1415926455 (0.0000002573% err) 590:100798 / 32085 = 3.1415926445 (0.0000002881% err) 588:100443 / 31972 = 3.1415926435 (0.0000003192% err) 586:100088 / 31859 = 3.1415926425 (0.0000003504% err) 584:99733 / 31746 = 3.1415926415 (0.0000003819% err) 582:99378 / 31633 = 3.1415926406 (0.0000004136% err) 580:99023 / 31520 = 3.1415926395 (0.0000004455% err) 578:98668 / 31407 = 3.1415926385 (0.0000004777% err) 576:98313 / 31294 = 3.1415926375 (0.0000005100% err) 574:97958 / 31181 = 3.1415926365 (0.0000005427% err) 572:97603 / 31068 = 3.1415926355 (0.0000005755% err) 570:97248 / 30955 = 3.1415926344 (0.0000006086% err) 568:96893 / 30842 = 3.1415926334 (0.0000006420% err) 566:96538 / 30729 = 3.1415926323 (0.0000006755% err) 564:96183 / 30616 = 3.1415926313 (0.0000007094% err) 562:95828 / 30503 = 3.1415926302 (0.0000007435% err) 560:95473 / 30390 = 3.1415926291 (0.0000007778% err) 558:95118 / 30277 = 3.1415926280 (0.0000008124% err) 556:94763 / 30164 = 3.1415926269 (0.0000008473% err) 554:94408 / 30051 = 3.1415926258 (0.0000008824% err) 552:94053 / 29938 = 3.1415926247 (0.0000009177% err) 550:93698 / 29825 = 3.1415926236 (0.0000009534% err) 548:93343 / 29712 = 3.1415926225 (0.0000009893% err) 546:92988 / 29599 = 3.1415926213 (0.0000010255% err) 544:92633 / 29486 = 3.1415926202 (0.0000010620% err) 542:92278 / 29373 = 3.1415926190 (0.0000010987% err) 540:91923 / 29260 = 3.1415926179 (0.0000011358% err) 538:91568 / 29147 = 3.1415926167 (0.0000011731% err) 536:91213 / 29034 = 3.1415926155 (0.0000012107% err) 534:90858 / 28921 = 3.1415926143 (0.0000012486% err) 532:90503 / 28808 = 3.1415926131 (0.0000012868% err) 530:90148 / 28695 = 3.1415926119 (0.0000013253% err) 528:89793 / 28582 = 3.1415926107 (0.0000013641% err) 526:89438 / 28469 = 3.1415926095 (0.0000014033% err) 524:89083 / 28356 = 3.1415926082 (0.0000014427% err) 522:88728 / 28243 = 3.1415926070 (0.0000014824% err) 520:88373 / 28130 = 3.1415926057 (0.0000015225% err) 518:88018 / 28017 = 3.1415926044 (0.0000015629% err) 516:87663 / 27904 = 3.1415926032 (0.0000016036% err) 514:87308 / 27791 = 3.1415926019 (0.0000016447% err) 512:86953 / 27678 = 3.1415926006 (0.0000016860% err) 762:Based on a recent addition, this approximation: 510:86598 / 27565 = 3.141592599 (0.0000017278% err) 508:86243 / 27452 = 3.141592597 (0.0000017698% err) 506:85888 / 27339 = 3.141592596 (0.0000018122% err) 504:85533 / 27226 = 3.141592595 (0.0000018550% err) 502:85178 / 27113 = 3.141592593 (0.0000018981% err) 500:84823 / 27000 = 3.141592592 (0.0000019416% err) 498:84468 / 26887 = 3.141592591 (0.0000019854% err) 496:84113 / 26774 = 3.141592589 (0.0000020297% err) 494:83758 / 26661 = 3.141592588 (0.0000020743% err) 492:83403 / 26548 = 3.141592587 (0.0000021192% err) 490:83048 / 26435 = 3.141592585 (0.0000021646% err) 488:82693 / 26322 = 3.141592584 (0.0000022103% err) 486:82338 / 26209 = 3.141592582 (0.0000022565% err) 484:81983 / 26096 = 3.141592581 (0.0000023030% err) 482:81628 / 25983 = 3.141592579 (0.0000023500% err) 480:81273 / 25870 = 3.141592578 (0.0000023973% err) 478:80918 / 25757 = 3.141592576 (0.0000024451% err) 476:80563 / 25644 = 3.141592575 (0.0000024933% err) 474:80208 / 25531 = 3.141592573 (0.0000025419% err) 472:79853 / 25418 = 3.141592572 (0.0000025909% err) 470:79498 / 25305 = 3.141592570 (0.0000026404% err) 468:79143 / 25192 = 3.141592569 (0.0000026904% err) 466:78788 / 25079 = 3.141592567 (0.0000027407% err) 464:78433 / 24966 = 3.141592565 (0.0000027916% err) 462:78078 / 24853 = 3.141592564 (0.0000028429% err) 460:77723 / 24740 = 3.141592562 (0.0000028947% err) 458:77368 / 24627 = 3.141592561 (0.0000029469% err) 456:77013 / 24514 = 3.141592559 (0.0000029996% err) 454:76658 / 24401 = 3.141592557 (0.0000030528% err) 452:76303 / 24288 = 3.141592555 (0.0000031065% err) 450:75948 / 24175 = 3.141592554 (0.0000031608% err) 448:75593 / 24062 = 3.141592552 (0.0000032155% err) 446:75238 / 23949 = 3.141592550 (0.0000032707% err) 444:74883 / 23836 = 3.141592549 (0.0000033265% err) 442:74528 / 23723 = 3.141592547 (0.0000033828% err) 440:74173 / 23610 = 3.141592545 (0.0000034396% err) 438:73818 / 23497 = 3.141592543 (0.0000034970% err) 436:73463 / 23384 = 3.141592541 (0.0000035549% err) 434:73108 / 23271 = 3.141592540 (0.0000036134% err) 432:72753 / 23158 = 3.141592538 (0.0000036725% err) 430:72398 / 23045 = 3.141592536 (0.0000037321% err) 428:72043 / 22932 = 3.141592534 (0.0000037923% err) 426:71688 / 22819 = 3.141592532 (0.0000038532% err) 424:71333 / 22706 = 3.141592530 (0.0000039146% err) 422:70978 / 22593 = 3.141592528 (0.0000039767% err) 420:70623 / 22480 = 3.141592526 (0.0000040393% err) 418:70268 / 22367 = 3.141592524 (0.0000041026% err) 416:69913 / 22254 = 3.141592522 (0.0000041666% err) 414:69558 / 22141 = 3.141592520 (0.0000042312% err) 412:69203 / 22028 = 3.141592518 (0.0000042965% err) 410:68848 / 21915 = 3.141592516 (0.0000043624% err) 408:68493 / 21802 = 3.141592514 (0.0000044290% err) 406:68138 / 21689 = 3.141592512 (0.0000044963% err) 404:67783 / 21576 = 3.141592510 (0.0000045643% err) 402:67428 / 21463 = 3.141592508 (0.0000046331% err) 400:67073 / 21350 = 3.141592505 (0.0000047026% err) 398:66718 / 21237 = 3.141592503 (0.0000047728% err) 396:66363 / 21124 = 3.141592501 (0.0000048437% err) 394:66008 / 21011 = 3.141592499 (0.0000049154% err) 392:65653 / 20898 = 3.141592496 (0.0000049879% err) 390:65298 / 20785 = 3.141592494 (0.0000050612% err) 388:64943 / 20672 = 3.141592492 (0.0000051353% err) 386:64588 / 20559 = 3.141592489 (0.0000052102% err) 384:64233 / 20446 = 3.141592487 (0.0000052859% err) 382:63878 / 20333 = 3.141592485 (0.0000053625% err) 380:63523 / 20220 = 3.141592482 (0.0000054399% err) 378:63168 / 20107 = 3.141592480 (0.0000055182% err) 376:62813 / 19994 = 3.141592477 (0.0000055974% err) 374:62458 / 19881 = 3.141592475 (0.0000056774% err) 372:62103 / 19768 = 3.141592472 (0.0000057584% err) 370:61748 / 19655 = 3.141592470 (0.0000058404% err) 368:61393 / 19542 = 3.141592467 (0.0000059232% err) 366:61038 / 19429 = 3.141592464 (0.0000060071% err) 364:60683 / 19316 = 3.141592462 (0.0000060919% err) 362:60328 / 19203 = 3.141592459 (0.0000061777% err) 360:59973 / 19090 = 3.141592456 (0.0000062645% err) 358:59618 / 18977 = 3.141592454 (0.0000063524% err) 356:59263 / 18864 = 3.141592451 (0.0000064413% err) 354:58908 / 18751 = 3.141592448 (0.0000065313% err) 352:58553 / 18638 = 3.141592445 (0.0000066224% err) 350:58198 / 18525 = 3.141592442 (0.0000067146% err) 348:57843 / 18412 = 3.141592439 (0.0000068079% err) 346:57488 / 18299 = 3.141592436 (0.0000069024% err) 344:57133 / 18186 = 3.141592433 (0.0000069980% err) 342:56778 / 18073 = 3.141592430 (0.0000070949% err) 340:56423 / 17960 = 3.141592427 (0.0000071929% err) 338:56068 / 17847 = 3.141592424 (0.0000072922% err) 336:55713 / 17734 = 3.141592421 (0.0000073928% err) 334:55358 / 17621 = 3.141592418 (0.0000074947% err) 332:55003 / 17508 = 3.141592414 (0.0000075979% err) 330:54648 / 17395 = 3.141592411 (0.0000077024% err) 328:54293 / 17282 = 3.141592408 (0.0000078083% err) 326:53938 / 17169 = 3.141592404 (0.0000079155% err) 324:53583 / 17056 = 3.141592401 (0.0000080242% err) 322:53228 / 16943 = 3.141592398 (0.0000081344% err) 320:52873 / 16830 = 3.141592394 (0.0000082460% err) 318:52518 / 16717 = 3.141592390 (0.0000083592% err) 316:52163 / 16604 = 3.141592387 (0.0000084738% err) 922:best approximation of pi they could think of. 918:accurate to say that it treated pi as 256/81. 634:which is more accurate and needs less digits. 944:Ramanujan's approximation in his 1914 paper: 880:= 3.125, about 0.528% below the exact value. 214:This page has archives. Sections older than 18:Talk:History of numerical approximations of π 8: 296:22 / 7 = 3.142857 (0.04025% err) << 243: 58: 2009: 1997: 1977: 1965: 1945: 1933: 1918: 1735: 1688: 1682: 1671: 1637: 1616: 1610: 1599: 1579: 1570: 1561: 1540: 1519: 1501: 1495: 1458: 1446: 1440: 1422: 1416: 1382: 1369: 1356: 1344: 1326: 1320: 1287: 1274: 1256: 1250: 1201: 1154: 1148: 1137: 1103: 1079: 1073: 1062: 1042: 1033: 1024: 1003: 982: 964: 952: 833: 802: 792: 789: 779: 769: 767: 742: 740: 718: 716: 288:3 / 1 = 3.000 (4.507% err) <<< 224:when more than 10 sections are present. 60: 30: 2069: 666:my calculator shows the result to be 2047:Royal Naval College, Eaton, Chester. 883:At about the same time, the Egyptian 7: 2039:86021 39494 63952 24737 (D. F. F.). 312:333 / 106 = 3.141509 (0.00265% err) 106:This article is within the scope of 310:311 / 99 = 3.141414 (0.00568% err) 308:289 / 92 = 3.141304 (0.00918% err) 306:267 / 85 = 3.141176 (0.01325% err) 304:245 / 78 = 3.141025 (0.01805% err) 302:223 / 71 = 3.140845 (0.02380% err) 300:201 / 64 = 3.140625 (0.03080% err) 298:179 / 57 = 3.140350 (0.03953% err) 49:It is of interest to the following 1683: 1611: 1149: 1074: 895:text) implies an approximation of 25: 2118:Mid-priority mathematics articles 2037:86021 39501 60924 48077 (Shanks). 286:fraction = approximation (error) 218:may be automatically archived by 126:Knowledge:WikiProject Mathematics 1312:is a simple approximation, but 663:trying to find it is always fun. 175: 129:Template:WikiProject Mathematics 93: 83: 62: 31: 1854:from Bryan Hayes' bibliography: 294:19 / 6 = 3.166667 (0.798% err) 146:This article has been rated as 1822:Chronology of computation of π 1742: 1732: 1717: 1711: 1644: 1628: 1537: 1525: 1513: 1507: 1434: 1428: 1338: 1332: 1268: 1262: 1208: 1198: 1183: 1177: 1110: 1091: 1000: 988: 976: 970: 1: 2051:2601:644:8501:AAF0:0:0:0:98EB 1839:2601:644:8501:AAF0:0:0:0:2EE5 1553: 1016: 939: 683:02:58, 15 February 2023 (UTC) 120:and see a list of open tasks. 2113:C-Class mathematics articles 1791:Miscellaneous approximations 1786:21:59, 21 October 2023 (UTC) 706:05:24, 14 October 2022 (UTC) 292:16 / 5 = 3.200 (1.859% err) 290:13 / 4 = 3.250 (3.451% err) 274:20:37, 10 January 2024 (UTC) 2099:12:24, 21 August 2024 (UTC) 935:20:59, 22 August 2023 (UTC) 752:{\displaystyle {\sqrt {3}}} 728:{\displaystyle {\sqrt {2}}} 644:16:15, 18 August 2022 (UTC) 258:15:50, 9 January 2015 (UTC) 2134: 1809:22:14, 21 March 2024 (UTC) 889:Second Intermediate Period 885:Rhind Mathematical Papyrus 689:22/7 is definitely ancient 280:Fractional approximations 145: 78: 57: 2064:Digit extraction methods 2059:18:06, 21 May 2024 (UTC) 1847:10:32, 21 May 2024 (UTC) 864:Babylonian and Egypt Pi? 859:11:12, 30 May 2023 (UTC) 711:approximations based on 152:project's priority scale 940:Borwein's approximation 109:WikiProject Mathematics 2023: 1761: 1687: 1615: 1478: 1399: 1303: 1242:is odd. For example, 1227: 1153: 1078: 843: 753: 729: 656:( 355 -3015E-8 ) / 113 221:Lowercase sigmabot III 39:This article is rated 2024: 1762: 1667: 1595: 1479: 1400: 1304: 1228: 1133: 1058: 844: 754: 730: 1917: 1837:article is online. 1814:Ferguson calculation 1494: 1415: 1319: 1249: 951: 766: 739: 715: 132:mathematics articles 1881:Ferguson correction 2019: 1757: 1554: 1474: 1395: 1299: 1223: 1017: 839: 749: 725: 101:Mathematics portal 45:content assessment 2017: 1985: 1953: 1755: 1752: 1740: 1654: 1642: 1587: 1584: 1548: 1545: 1472: 1463: 1451: 1393: 1387: 1374: 1361: 1297: 1296: 1282: 1221: 1218: 1206: 1120: 1108: 1050: 1047: 1011: 1008: 828: 819: 807: 797: 784: 774: 747: 723: 260: 248:comment added by 228: 227: 166: 165: 162: 161: 158: 157: 16:(Redirected from 2125: 2082: 2078: 2028: 2026: 2025: 2020: 2018: 2010: 2005: 2004: 1986: 1978: 1973: 1972: 1954: 1946: 1941: 1940: 1895:10.1038/157342c0 1775: 1766: 1764: 1763: 1758: 1756: 1754: 1753: 1751: 1741: 1736: 1703: 1689: 1686: 1681: 1656: 1655: 1653: 1643: 1638: 1617: 1614: 1609: 1588: 1586: 1585: 1580: 1571: 1562: 1549: 1547: 1546: 1541: 1520: 1506: 1505: 1483: 1481: 1480: 1475: 1473: 1471: 1464: 1459: 1453: 1452: 1447: 1441: 1427: 1426: 1404: 1402: 1401: 1396: 1394: 1389: 1388: 1383: 1375: 1370: 1362: 1357: 1345: 1331: 1330: 1308: 1306: 1305: 1300: 1298: 1289: 1288: 1283: 1275: 1261: 1260: 1241: 1232: 1230: 1229: 1224: 1222: 1220: 1219: 1217: 1207: 1202: 1169: 1155: 1152: 1147: 1122: 1121: 1119: 1109: 1104: 1080: 1077: 1072: 1051: 1049: 1048: 1043: 1034: 1025: 1012: 1010: 1009: 1004: 983: 969: 968: 848: 846: 845: 840: 838: 837: 827: 820: 815: 808: 803: 798: 793: 790: 785: 780: 775: 770: 758: 756: 755: 750: 748: 743: 734: 732: 731: 726: 724: 719: 223: 207: 179: 171: 134: 133: 130: 127: 124: 103: 98: 97: 87: 80: 79: 74: 66: 59: 42: 36: 35: 27: 21: 2133: 2132: 2128: 2127: 2126: 2124: 2123: 2122: 2103: 2102: 2080: 2076: 2066: 1993: 1961: 1929: 1915: 1914: 1883: 1874:10.2307/3608485 1816: 1793: 1771: 1704: 1690: 1657: 1621: 1575: 1563: 1524: 1497: 1492: 1491: 1454: 1442: 1418: 1413: 1412: 1346: 1322: 1317: 1316: 1252: 1247: 1246: 1237: 1170: 1156: 1123: 1084: 1038: 1026: 987: 960: 949: 948: 942: 902: 879: 866: 829: 791: 764: 763: 760: 737: 736: 713: 712: 691: 282: 233: 231:Wallis product? 219: 208: 202: 184: 131: 128: 125: 122: 121: 99: 92: 72: 43:on Knowledge's 40: 23: 22: 15: 12: 11: 5: 2131: 2129: 2121: 2120: 2115: 2105: 2104: 2065: 2062: 2046: 2045:D. F. Ferguson 2038: 2016: 2013: 2008: 2003: 2000: 1996: 1992: 1989: 1984: 1981: 1976: 1971: 1968: 1964: 1960: 1957: 1952: 1949: 1944: 1939: 1936: 1932: 1928: 1925: 1922: 1903: 1902: 1882: 1879: 1866: 1865: 1815: 1812: 1792: 1789: 1770:is valid when 1768: 1767: 1750: 1747: 1744: 1739: 1734: 1731: 1728: 1725: 1722: 1719: 1716: 1713: 1710: 1707: 1702: 1699: 1696: 1693: 1685: 1680: 1677: 1674: 1670: 1666: 1663: 1660: 1652: 1649: 1646: 1641: 1636: 1633: 1630: 1627: 1624: 1620: 1613: 1608: 1605: 1602: 1598: 1594: 1591: 1583: 1578: 1574: 1569: 1566: 1560: 1557: 1552: 1544: 1539: 1536: 1533: 1530: 1527: 1523: 1518: 1515: 1512: 1509: 1504: 1500: 1485: 1484: 1470: 1467: 1462: 1457: 1450: 1445: 1439: 1436: 1433: 1430: 1425: 1421: 1406: 1405: 1392: 1386: 1381: 1378: 1373: 1368: 1365: 1360: 1355: 1352: 1349: 1343: 1340: 1337: 1334: 1329: 1325: 1310: 1309: 1295: 1292: 1286: 1281: 1278: 1273: 1270: 1267: 1264: 1259: 1255: 1236:is valid when 1234: 1233: 1216: 1213: 1210: 1205: 1200: 1197: 1194: 1191: 1188: 1185: 1182: 1179: 1176: 1173: 1168: 1165: 1162: 1159: 1151: 1146: 1143: 1140: 1136: 1132: 1129: 1126: 1118: 1115: 1112: 1107: 1102: 1099: 1096: 1093: 1090: 1087: 1083: 1076: 1071: 1068: 1065: 1061: 1057: 1054: 1046: 1041: 1037: 1032: 1029: 1023: 1020: 1015: 1007: 1002: 999: 996: 993: 990: 986: 981: 978: 975: 972: 967: 963: 959: 956: 941: 938: 900: 893:Middle Kingdom 887:(dated to the 877: 865: 862: 836: 832: 826: 823: 818: 814: 811: 806: 801: 796: 788: 783: 778: 773: 759: 746: 722: 709: 690: 687: 686: 685: 671: 664: 661: 658: 653: 650: 632: 629: 627: 625: 623: 621: 619: 617: 615: 613: 611: 609: 607: 605: 603: 601: 599: 597: 595: 593: 591: 589: 587: 585: 583: 581: 579: 577: 575: 573: 571: 569: 567: 565: 563: 561: 559: 557: 555: 553: 551: 549: 547: 545: 543: 541: 539: 537: 535: 533: 531: 529: 527: 525: 523: 521: 519: 517: 515: 513: 511: 509: 507: 505: 503: 501: 499: 497: 495: 493: 491: 489: 487: 485: 483: 481: 479: 477: 475: 473: 471: 469: 467: 465: 463: 461: 459: 457: 455: 453: 451: 449: 447: 445: 443: 441: 439: 437: 435: 433: 431: 429: 427: 425: 423: 421: 419: 417: 415: 413: 411: 409: 407: 405: 403: 401: 399: 397: 395: 393: 391: 389: 387: 385: 383: 381: 379: 377: 375: 373: 371: 369: 367: 365: 363: 361: 359: 357: 355: 353: 351: 349: 347: 345: 343: 341: 339: 337: 335: 333: 331: 329: 327: 325: 323: 321: 319: 317: 315: 313: 311: 309: 307: 305: 303: 301: 299: 297: 295: 293: 291: 289: 287: 285: 281: 278: 277: 276: 237:Wallis product 232: 229: 226: 225: 213: 210: 209: 204: 200: 198: 195: 194: 186: 185: 180: 174: 168: 164: 163: 160: 159: 156: 155: 144: 138: 137: 135: 118:the discussion 105: 104: 88: 76: 75: 67: 55: 54: 48: 37: 24: 14: 13: 10: 9: 6: 4: 3: 2: 2130: 2119: 2116: 2114: 2111: 2110: 2108: 2101: 2100: 2096: 2092: 2087: 2084: 2073: 2071: 2063: 2061: 2060: 2056: 2052: 2048: 2043: 2040: 2035: 2032: 2029: 2014: 2011: 2006: 2001: 1998: 1994: 1990: 1987: 1982: 1979: 1974: 1969: 1966: 1962: 1958: 1955: 1950: 1947: 1942: 1937: 1934: 1930: 1926: 1923: 1920: 1912: 1909: 1906: 1900: 1899: 1898: 1896: 1892: 1888: 1880: 1878: 1875: 1871: 1864: 1859: 1858: 1857: 1856: 1853: 1849: 1848: 1844: 1840: 1836: 1833:article, but 1832: 1827: 1824:. The cited 1823: 1819: 1813: 1811: 1810: 1806: 1802: 1798: 1790: 1788: 1787: 1783: 1779: 1774: 1748: 1745: 1737: 1729: 1726: 1723: 1720: 1714: 1708: 1705: 1700: 1697: 1694: 1691: 1678: 1675: 1672: 1668: 1664: 1661: 1658: 1650: 1647: 1639: 1634: 1631: 1625: 1622: 1618: 1606: 1603: 1600: 1596: 1592: 1589: 1581: 1576: 1572: 1567: 1564: 1558: 1555: 1550: 1542: 1534: 1531: 1528: 1521: 1516: 1510: 1502: 1498: 1490: 1489: 1488: 1468: 1465: 1460: 1455: 1448: 1443: 1437: 1431: 1423: 1419: 1411: 1410: 1409: 1390: 1384: 1379: 1376: 1371: 1366: 1363: 1358: 1353: 1350: 1347: 1341: 1335: 1327: 1323: 1315: 1314: 1313: 1293: 1290: 1284: 1279: 1276: 1271: 1265: 1257: 1253: 1245: 1244: 1243: 1240: 1214: 1211: 1203: 1195: 1192: 1189: 1186: 1180: 1174: 1171: 1166: 1163: 1160: 1157: 1144: 1141: 1138: 1134: 1130: 1127: 1124: 1116: 1113: 1105: 1100: 1097: 1094: 1088: 1085: 1081: 1069: 1066: 1063: 1059: 1055: 1052: 1044: 1039: 1035: 1030: 1027: 1021: 1018: 1013: 1005: 997: 994: 991: 984: 979: 973: 965: 961: 957: 954: 947: 946: 945: 937: 936: 932: 928: 927:Nymathteacher 923: 919: 915: 911: 908: 906: 898: 894: 890: 886: 881: 875: 871: 863: 861: 860: 856: 852: 834: 830: 824: 821: 816: 812: 809: 804: 799: 794: 786: 781: 776: 771: 744: 720: 708: 707: 703: 699: 698:97.113.48.144 694: 688: 684: 680: 676: 675:Criticatlarge 672: 669: 665: 662: 659: 657: 654: 651: 648: 647: 646: 645: 641: 637: 631:103638/32989. 279: 275: 271: 267: 263: 262: 261: 259: 255: 251: 250:86.121.137.79 247: 242: 238: 230: 222: 217: 212: 211: 197: 196: 193: 192: 188: 187: 183: 178: 173: 172: 169: 153: 149: 143: 140: 139: 136: 119: 115: 111: 110: 102: 96: 91: 89: 86: 82: 81: 77: 71: 68: 65: 61: 56: 52: 46: 38: 34: 29: 28: 19: 2088: 2085: 2074: 2067: 2049: 2044: 2041: 2036: 2033: 2030: 1913: 1910: 1907: 1904: 1886: 1884: 1867: 1861: 1851: 1850: 1834: 1830: 1825: 1817: 1794: 1772: 1769: 1486: 1407: 1311: 1238: 1235: 943: 924: 920: 916: 912: 909: 896: 882: 873: 867: 761: 695: 692: 668:3.1415926535 667: 655: 283: 244:— Preceding 234: 215: 189: 181: 167: 148:Mid-priority 147: 107: 73:Mid‑priority 51:WikiProjects 1797:WP:SPAMBAIT 825:3.141592644 235:Should the 123:Mathematics 114:mathematics 70:Mathematics 2107:Categories 2091:GoldenRing 1901:Value of π 1831:Chronology 1391:1446914567 1348:1037785473 1801:Anita5192 1380:311451846 1367:192518946 1354:70101072 246:unsigned 216:365 days 182:Archives 905:octagon 670:(39623) 150:on the 41:C-class 1887:Nature 1852:Added: 1835:Nature 1826:Nature 1778:Nei.jp 1487:where 851:Dhrm77 636:Dhrm77 264:Done. 47:scale. 2095:talk 2055:talk 2015:1985 1843:talk 1805:talk 1782:talk 931:talk 899:as ⁄ 876:as ⁄ 870:Susa 855:talk 817:3921 735:and 702:talk 679:talk 673:qed 640:talk 270:talk 266:Wqwt 254:talk 2081:n→∞ 1995:tan 1963:tan 1931:tan 1897:): 1891:doi 1870:doi 1706:exp 1623:exp 1469:148 1172:exp 1086:exp 907:." 142:Mid 2109:: 2097:) 2083:. 2057:) 2007:⁡ 1999:− 1983:20 1975:⁡ 1967:− 1943:⁡ 1935:− 1927:12 1921:π 1845:) 1807:) 1799:.— 1784:) 1746:− 1727:− 1715:π 1709:⁡ 1698:− 1684:∞ 1669:∑ 1665:24 1648:− 1632:π 1626:⁡ 1612:∞ 1597:∑ 1593:24 1590:− 1577:π 1568:− 1532:− 1499:π 1466:− 1461:29 1456:33 1444:66 1432:58 1420:π 1385:58 1372:29 1336:58 1324:π 1266:25 1254:π 1193:− 1181:π 1175:⁡ 1164:− 1150:∞ 1135:∑ 1131:24 1128:− 1114:− 1098:π 1089:⁡ 1075:∞ 1060:∑ 1056:24 1053:− 1040:π 1031:− 995:− 962:π 958:≈ 955:π 933:) 901:81 857:) 813:18 810:− 800:− 704:) 681:) 642:) 272:) 256:) 2093:( 2077:n 2053:( 2012:1 2002:1 1991:4 1988:+ 1980:1 1970:1 1959:4 1956:+ 1951:4 1948:1 1938:1 1924:= 1893:: 1872:: 1841:( 1803:( 1780:( 1773:n 1749:1 1743:) 1738:n 1733:) 1730:1 1724:r 1721:2 1718:( 1712:( 1701:1 1695:r 1692:2 1679:1 1676:= 1673:r 1662:+ 1659:1 1651:1 1645:) 1640:n 1635:r 1629:( 1619:r 1607:1 1604:= 1601:r 1582:n 1573:6 1565:1 1559:= 1556:S 1551:, 1543:n 1538:) 1535:S 1529:1 1526:( 1522:6 1517:= 1514:) 1511:n 1508:( 1503:4 1449:2 1438:= 1435:) 1429:( 1424:4 1377:+ 1364:+ 1359:2 1351:+ 1342:= 1339:) 1333:( 1328:1 1294:5 1291:9 1285:+ 1280:5 1277:9 1272:= 1269:) 1263:( 1258:1 1239:n 1215:1 1212:+ 1209:) 1204:n 1199:) 1196:1 1190:r 1187:2 1184:( 1178:( 1167:1 1161:r 1158:2 1145:1 1142:= 1139:r 1125:1 1117:1 1111:) 1106:n 1101:r 1095:2 1092:( 1082:r 1070:1 1067:= 1064:r 1045:n 1036:3 1028:1 1022:= 1019:R 1014:, 1006:n 1001:) 998:R 992:1 989:( 985:3 980:= 977:) 974:n 971:( 966:1 929:( 897:π 878:8 874:π 853:( 835:+ 831:0 822:= 805:3 795:2 787:+ 782:3 777:+ 772:2 745:3 721:2 700:( 677:( 638:( 268:( 252:( 191:1 154:. 53:: 20:)

Index

Talk:History of numerical approximations of π

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1
Lowercase sigmabot III
Wallis product
http://math.stackexchange.com/questions/1097633/how-to-show-frac-pi4-frac2-cdot4-cdot4-cdot6-cdot6-cdot8-dotsm3-cdot
unsigned
86.121.137.79
talk
15:50, 9 January 2015 (UTC)
Wqwt
talk
20:37, 10 January 2024 (UTC)
Dhrm77
talk
16:15, 18 August 2022 (UTC)
Criticatlarge

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